Manufacturing processes of a semiconductor device (semiconductor chip) are classified broadly into a process of forming a semiconductor element part which has a semiconductor circuit, a wiring layer and the like in correspondence with a chip area in a surface of a semiconductor wafer, and a process (segmenting process) of cutting the semiconductor wafer in correspondence with the chip area (chip shape). In processing the semiconductor wafer, a process called dicing before grinding is applied as a processing process to combine film thinning of a wafer with segmentation of a chip. In the dicing before grinding process, first, there is formed a groove which is shallower than a wafer thickness and deeper than a chip thickness after completion in a semiconductor wafer from a front surface side in which a semiconductor element part is formed. Next, after a protective film is attached to a front surface of the semiconductor wafer, a rear surface of the semiconductor wafer is ground, so that the semiconductor wafer is segmented into respective chips.
A sheet-shaped adhesive film and supporting film are attached to the rear surface of the semiconductor wafer whose entire shape is maintained by a surface protective film. The adhesive film functions as an adhesive layer for each chip and is cut (segmented) in correspondence with each chip shape. The adhesive film is cut, after the surface protective film is peeled for example, by radiating a laser beam along a dicing groove from the front surface side of the semiconductor wafer. There is suggested a method in which the adhesive film is cut as a result that the supporting film to which the semiconductor wafer is attached is expanded in a horizontal direction to selectively modify the adhesive film existing between the chips.
In a method for cutting the adhesive film by the laser beam, since an alignment property of the chips is apt to deteriorate in repetition of attaching of the semiconductor wafer, a cutting speed of the adhesive film is reduced and the number of cutting actions tends to increase. Further, there is a possibility that waste occurring at a time of cutting the adhesive film by the laser beam contaminates the semiconductor chip. In the method for selectively modifying the adhesive film, a cost necessary for modification tends to increase a cutting cost, and there is a possibility that a cutting property of the adhesive film cannot be sufficiently heightened depending on modifying methods. Thus, in forming an adhesive layer in a rear surface of a semiconductor wafer segmented in a chip shape by dicing before grinding or the like, it is required to heighten a cutting property of the adhesive layer and to suppress contamination or the like of a semiconductor chip at a time of cutting of the adhesive layer.